This invention relates to high temperature fluid transmission piping, and more particularly to a rotary pipe coupling having apparatus for cooling the pressure seals.
In certain types of steam generating systems, the steam pipelines must be shifted from one position to another. For example, in a distributed solar energy collection system, the position of the steam generator must be shifted frequently to compensate for the motion of the sun. In such applications, the steam piping must have a number of rotary pipe couplings. Therefore, there is a need for a rotary joint that is mechanically reliable, has little fluid or thermal leakage, and rotates with minimal friction.
High-temperature rotary couplings are not new to the art, as shown by U.S. Pat. No. 3,057,646 to Brumagim which discloses a coupling that connects abutting steam pipes, and has a conduction path for carrying a fluid to cool the pressure seal. U.S. Pat. No. 2,127,073 to Topping illustrates an air-cooled steam pipe expansion joint in which the packing material is thermally isolated to some extent from the high-temperature fluid. These devices, however, do not provide the pressure seal thermal isolation, design simplicity, balanced pressure, and mechanical flexiblity called for in current dynamic fluid piping systems.